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The Haber process is a high-temperasture high-pressure process for combining [[nitrogen]] and [[hydrogen]] gasses into [[ammonia]]. The reaction is relatively inefficient, with ~5% yield per iteration.
The Haber Process is a vital industrial process which produces "fixed" nitrogen from atmospheric nitrogen, allowing the production of fertilizers and other nitrogen-based compounds. Hydrogen and nitrogen are run over a heated catalyst at pressure and bond to produce [[ammonia]].
: {{#Chem: N2 + 3H2 { Fe = 20MPa, 500-600°C } 2NH3}}
==Process==
===Atmospheric pressure===
====plain iron oxide====
Simple iron oxide can be used as a catalyst.
* The catalyst is purified {{#Chem:  Fe3O4}} ([[magnetite]]) with the oxygen removed by exposure to [[hydrogen]] at high temperatures. This provides the appropriate porosity.
* The reaction takes place at 440-450°C and atmospheric pressure
* Yield is 0.25% ammonia
* Scaling: 100-200cc of gas per minute over 1kg of catalyst
See "The Direct Synthesis of Ammonia"<ref>{{cite pub|publication=J. Chem. Educ.|title=The Direct Synthesis of Ammonia: A lecture table experiment|first1=Alfred T.|last1=Lars|url=http://pubs.acs.org/doi/pdf/10.1021/ed002p285|year=1925}}</ref> for a description of producing the catalyst.
 
====platinum====
===High Pressure===
====platinum====
* Yield: 4-5%
====promoted iron====
* The catalyst is doped purified iron {{#Chem: Fe + CaO + K2O + SiO2 + Al3O4}}
* The reaction takes place at 300–550 &deg;C and 50–250 atmospheres.
* Yield is over 90%
 
The gasses are refrigerated, the ammonia removed as a liquid, and the process is repeated. Iron oxide can be used in place of iron, because it will be rapidly reduced by the hydrogen gas to water and pure iron.
The gasses are refrigerated, the ammonia removed as a liquid, and the process is repeated. Iron oxide can be used in place of iron, because it will be rapidly reduced by the hydrogen gas to water and pure iron.


Revision as of 01:05, 1 May 2020

The Haber Process is a vital industrial process which produces "fixed" nitrogen from atmospheric nitrogen, allowing the production of fertilizers and other nitrogen-based compounds. Hydrogen and nitrogen are run over a heated catalyst at pressure and bond to produce ammonia.

Process

Atmospheric pressure

plain iron oxide

Simple iron oxide can be used as a catalyst.

  • The catalyst is purified Fe3O4 (magnetite) with the oxygen removed by exposure to hydrogen at high temperatures. This provides the appropriate porosity.
  • The reaction takes place at 440-450°C and atmospheric pressure
  • Yield is 0.25% ammonia
  • Scaling: 100-200cc of gas per minute over 1kg of catalyst

See "The Direct Synthesis of Ammonia"[1] for a description of producing the catalyst.

platinum

High Pressure

platinum

  • Yield: 4-5%

  • The catalyst is doped purified iron Fe + CaO + K2O + SiO2 + Al3O4
  • The reaction takes place at 300–550 °C and 50–250 atmospheres.
  • Yield is over 90%

The gasses are refrigerated, the ammonia removed as a liquid, and the process is repeated. Iron oxide can be used in place of iron, because it will be rapidly reduced by the hydrogen gas to water and pure iron.

Apparently Tungsten can also be used as a catalyst at about 600°C and atmospheric pressure.[2]

Hazards

  • At the extremely high temperatures and pressures involved, rupture and explosion of the reaction vessel is a serious concern.

See Also

References

  1. ↑ Lars, Alfred T. (1925) "The Direct Synthesis of Ammonia: A lecture table experiment"
    J. Chem. Educ. 
  2. ↑ Fromm, F. (1942) "Lecture experiment on the synthesis and combustion of ammonia"; pp230.
    DOI:https://doi.org/10.1021/ed019p230
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